The show revolved around two police officers who investigated homicides in San Francisco. The center of the series was a veteran cop and widower, Lt Mike Stone (Karl Malden), who had more than 20 years of police experience and was now assigned to the Homicide Detail of SFPD's Bureau of Inspectors. He was partnered with a young, energetic partner, Assistant Inspector Steve Keller (Michael Douglas), a college graduate, age 28, who had no police experience. Stone would become a second father to Keller as he learned the rigors and procedures of detective work.